Field of the Invention
This invention relates generally to display systems, and more particularly to display systems including an array of individual pixel cells. Even more particularly, this invention relates to display systems wherein pixel data is asserted on individual pixels of the display.
Description of the Background Art
Display systems including arrays of pixels upon which display data is asserted are well known. In prior art displays, the pixels are typically arranged in an array of columns and rows. Data lines are arranged along each column of pixels, and row lines are arranged along each row of pixels. An enable signal on a particular row line causes each pixel of the row to load the data bit being asserted on the respective column lines (usually two) associated with each particular pixel into an internal latch of the pixel. The latched data bit controls the intensity displayed by the associated pixel.
Multiple bits of data (e.g., 8 bits, 16 bits, or more) are sequentially loaded into each pixel to generate a single intensity value. Depending on the values of the data bits, the pixel switches between on/light (e.g., digital 1) and off/dark (e.g., digital 0) states, which are integrated by the eye of a viewer so that an intermediate intensity is perceived by the viewer.
Substantial power is consumed each time the column lines are recharged to write a digital 1 to a pixel. The number of times that the column lines must be recharged during a single frame of data depends on the content of the data. In particular, whenever a digital 0 is written to a pixel and a digital 1 is written to a pixel in the next row (same column), the column lines must be recharged. For a 1280×720 pixel display, the column lines must be recharged approximately 9 million times for a typical display picture, and can require in excess of 29 million recharges for worst case frames of data. Moreover, because the required number of column line recharges varies depending on the video data, power consumption is not consistent.
In order to improve image quality, different data schemes have been developed. In some cases, original data (e.g., 8-bit) is converted to data having a greater number of bits (e.g., in excess of 60 bits). The increased number of bits greatly increases the number of column line transitions and, therefore, also the power consumption of the display. In addition, the increased number of data bits requires larger memory buffers, which increases the cost of the display and/or driver circuits.
What is needed is a display that uses less power than prior art displays. What is also needed is a display with more consistent power consumption. What is also needed is a display that can achieve the results of driving schemes using an increased number of data bits, but without increasing the size of memory buffers within the display and/or driving circuits.